First, setup your formations. You have three formations (A, B and C), and each dictates where your heroes will stand and which of their skills they will use. When you're ready, Start the Battle!

When combat comes, enemies will spawn from the right of the screen. You'll be able to switch between your three formations, but beyond that your heroes will act entirely on their own.

Choose your formations wisely, switch between them appropriately, and try to hold out as long as you can! My high score's around 404,000; let me know if you can beat it!